Even though Twitter has been Apple’s pick of social networks to be integrated into iOS 7, it’s looking like LinkedIn could also make it to the chosen circle.

Developers have found code-based references to deep LinkedIn integration in the beta version of iOS 7, which was supplied by Apple, according to 9to5Mac. This code shows that a single sign-on system is in the works for the professional social network — much like how iOS currently works with Facebook and Twitter.

The developer that supplied 9to5Mac with the code sheets said that certain bits of code are missing for the integration to be activated. This could mean that Apple and LinkedIn are still currently in talks about the possible integration. According to 9to5Mac, Apple has tossed social networks from iOS integration before. For instance, iOS 4 tested Facebook integration, but it didn’t happen until iOS 6.

What exactly does deep integration mean? Well, for Twitter on iOS 7, it means a lot. Besides the social network being included in Shared Links, searches, and linked with Siri, there will also be a featured music station on Apple’s iTunes Radio that plays tracks trending on Twitter. For now, Facebook is only being integrated with iOS 7 — not deeply integrated.

When Apple announced the debut of iOS 7 at WWDC last week, it heralded many of the operating system’s new features, but it also left out some details. An initial beta of iOS 7 was released to developers last week, in what is expected to be the first of several ahead of its release. Over the last few days, several developers have been posting various tricks, updates, and features that they’ve discovered and believe will come with the new operating system.

Apple has not provided an exact date for its release, short of this fall, when the company is also expected to introduce its next iPhone. There are still no beta versions of iOS 7 available for iPads, just the iPhone and latest-generation iPod Touch.